Time Machine: Timecop Type, a giant sled shoots you back into the past, but you arrive with out said machine, you have a remote control that will get you back to the sled.
Fridge Logic: Said Time Machine seemly works by hurtling you in the giant sled towards a wall at high speed, sending you to the past before you hit it. There's a blood stain on the wall, supposedly from this not happening with a previous Time Cop. Why have a wall there if there's a chance you could end up hitting it? And why not at least clean off the blood afterwards? (It reminds time travelers that this is Serious Business?)
You won't even get to the fridge before wondering "Where does the sled go when they arrive walking in the past? How did they get back into it when they return?"
Fridge Brilliance: The sled and wall are all part of the apparatus - think particle accelerator slamming things together meets pinching a beanpod in just the right way that the bean shoots out of the pod rather than getting crushed in it. The passengers thus pass through the Timey-Wimey Ball into the past, and when they're ready to return, they trigger their remotes and return to the pod, which does a weird Stephen Hawking "cup reassembles on the floor and flies back onto the table" thingy.
Timey Wimey Wall?
Zeerust: Remember back in 2004, when we all had those self-driving, voice-activated cars that looked like this◊? That future got erased along with the time machines as the ultimate result of repeated attempts to alter the timeline. This is actually Larry Niven's Law of Time Travel: (paraphrased) "If a device capable of altering the past can be created, the past will be altered continuously until a timeline is created where that device does not exist."
Fridge Logic: The wall is there in case the time-field gets inverted, which would hurl people into the future with knowledge of the present. It works by ensuring that nobody can possibly survive a trip into the future; the wall will still be there. Perhaps there are strict regulations regarding just when (or if) they're allowed to remove the wall.